1. Field of the Invention
The present invention relates to a power source output control system for a vehicle.
2. Description of the Prior Art
As in the power source output control systems for vehicles, the following systems are conventionally known: a control system in which a target driving force is determined on the basis of an accelerator operation amount for controlling the opening degree of a throttle valve (Japanese Patent Application Laid-open No. 164632/85); a control system in which a target driving force is determined from an accelerator operation amount, an engine revolution number and an external load amount for controlling the opening degree of a throttle valve and the amount of fuel supplied (Japanese Patent Application Laid-open No. 313636/89); and a control system in which the opening degree of a throttle valve is controlled so that the target driving force is varied uniformly with respect to a variation in accelerator operation amount (Japanese Patent Application Laid-open No. 102333/90).
In such control systems in which the target driving force is determined on the basis of the accelerator operation amount, the engine revolution number, and the like, for controlling the power source output, however, when the travel resistance is varied due to the weight of the vehicle, the wind and the travelling on a sloping road, a vehicle's driver must conduct a correcting operation in accordance with the variation in travel resistance and this is troublesome.